Abstract: SA-PO094

Comparison of Measured versus Online Urea Kinetics in Patients with AKI Undergoing Hemodialysis

Session Information

Category: Acute Kidney Injury

  • 003 AKI: Clinical and Translational


  • Bhatti, Owais, Washington University St Louis, Saint Louis, Missouri, United States
  • Zhang, Yifei Frank, Washington University St Louis, Saint Louis, Missouri, United States
  • Vijayan, Anitha, Washington University St Louis, Saint Louis, Missouri, United States

In patients with acute kidney injury (AKI) on intermittent hemodialysis (HD), KDIGO guidelines recommend a target single pool Kt/V (spKt/V) of 1.3, three times per week. Currently, the standard method of monitoring dialysis adequacy is by calculating spKt/V using pre and post serum BUN. This requires additional blood draws which are associated with nursing labor and laboratory costs. Online urea kinetic monitor systems, such as continuous dialysate UV-adsorbance monitoring, can potentially measure real time spKt/V without added cost. Unlike ESRD, AKI patients have fluctuating volume of distribution of urea and data on online urea monitoring in AKI are scarce.


We instituted a QI project to compare online monitoring to measured Kt/Vurea. After approval from the Washington University IRB we conducted a retrospective analysis of this data. For a single dialysis session per patient, spKt/V was calculated via Daugirdas equation, and compared to Kt/V measured by dialysate online urea monitoring. All patients underwent HD using B.Braun Dialog+(R) machines. Data were analyzed using Bland-Altman analysis.


We reviewed 43 dialysis treatments of 20 patients with AKI. The mean age was 53 years, 60 % (12) were men and 65 % (13) had ATN. Bland- Altman analyses of the data showed that both methods were in agreement (Fig 1).


In this pilot study, data suggest that spKt/V calculated via pre and post serum BUN is comparable to the Kt/Vurea measured by continuous dialysate monitoring using UV-adsorbance. This has major implications regarding cost savings while ensuring that AKI patients are receiving adequate dialysis. A larger prospective study is needed to determine whether online urea kinetics monitoring can be substituted for measured Kt/Vurea in patients with AKI.

Figure 1